1. Field of the Invention
The present invention is related generally to the therapeutic application of a peroxidized lipid or a composition containing a peroxidized lipid to promote wound healing and to treat circulatory insufficiencies and skin disorders, particularly in diabetics.
2. Related Art
It is known that many people suffer from circulatory insufficiency of arterial or venous origin, which is often chronic. Circulatory insufficiencies may be local and benign, manifested by, for example, a feeling of painful numbness at the finger ends caused by cold (tingling), or heaviness in the lower limbs. Circulatory insufficiencies may be manifested in much more serious forms associated with an arrest of the blood circulation (ischemia), which is capable of causing localized necrosis. Arterial or venous leg ulcers, for example, are the result of such a circulatory insufficiency and are a clinical manifestation of insufficient irrigation of the superficial and deep tissues by blood flow. Certain peroxidized lipids are known to have a high level of efficacy in tissue revascularization when applied topically. One use of such peroxidized lipids is known to promote increased blood flow in subjects patients suffering from male sexual asthenia, as disclosed in U.S. Pat. No. 5,254,585, issued on Oct. 19, 1993, which is hereby incorporated by reference in its entirety.
Chronic circulatory insufficiency is common in diabetic patients, who are particularly susceptible to problems and disorders associated with poor blood flow, particularly in the extremities. Diabetes affects nearly every part of the body, causing capillary blood vessels to narrow and harden. It has been estimated that up to about one third of diabetics will experience a skin disorder caused or aggravated by the disease. A skin disorder is often the first sign that a person has diabetes. Some skin disorders are common to many people but occur more often and more easily with diabetics. Chronic dry skin, bacterial infections, fungal infections, and itching, occur with many people, especially diabetics. Diabetic dermopathy, necrobiosis, lipodica diabeticorum, diabetic blisters, and eruptive xanthomatosis occur only among diabetics. Many treatments have been proposed for overcoming these insufficiencies. Thus, it has already been recommended to use numerous vasodilative or vasoprotective products by oral or percutaneous administration, often by perfusion. However, these products have many undesirable side-effects, so their use is restricted to the most serious cases of circulatory insufficiency.
Patients with chronic circulatory insufficiency, including diabetics, are particularly susceptible to problems with the wound healing process. The wound healing process involves a complex cascade of biochemical and cellular events to restore tissue integrity following an injury. The wound healing process is typically characterized by four stages: 1) hemostasis; 2) inflammation; 3) proliferation; and 4) remodeling. The synthesis of collagen, which accounts for about 90% of the proteins found in the human dermis, is known to play a role in the necessary biological cascade of wound healing. Collagen has diverse biological roles including morphogenesis (shaping and contouring), tissue repair, remodeling, cellular adhesion, cellular migration, chemotaxis and platelet aggregation. An important factor in the rate of production of collagen is adequate blood flow. Reduced blood flow is a primary causative factor in elongated wound healing time and is also related to the general health aspects of skin.
In one embodiment, the present invention is directed to a method for treating a wound in a subject with a diabetic condition. The method involves administering a peroxidized lipid to a subject in need of such treatment in an amount effective to promote wound healing in the subject.
In another embodiment, the method is directed to treating a wound in a subject with a diabetic condition otherwise free of symptoms of male sexual asthenia. The method involves administering a peroxidized lipid to a subject in need of such treatment in an amount effective to promote wound healing in the subject.
In another embodiment, the method involves treating a subject with a diabetic condition who has sustained a wound. The method involves administering a peroxidized lipid to a subject in need of such treatment in an amount effective to promote wound healing in the subject.
In another embodiment, the method involves treating a subject with a diabetic condition who has sustained a wound. The subject is otherwise free of symptoms of male sexual asthenia. The method involves administering a peroxidized lipid to a subject in need of such treatment in an amount effective to promote wound healing in the subject.
In another embodiment, the method involves treating a circulatory insufficiency in a subject with a diabetic condition, by administering a peroxidized lipid to a subject in need of such treatment in an amount effective to promote circulation in the subject.
In another embodiment, the method is directed to treating a diabetic skin disorder in a subject. The method involves administering a peroxidized lipid to a subject in need of such treatment in an amount effective to promote healing of the diabetic skin disorder.
According to each of the above-described embodiments, the peroxidized lipid includes at least one peroxide.
xe2x80x9cSubject,xe2x80x9d as used herein, shall mean a human or vertebrate animal including, but not limited to, a dog, cat, horse, cow, pig, sheep, goat, chicken, primate, e.g., monkey, rat, and mouse.
xe2x80x9cDiabetic subject: as used herein, shall mean a human or vertebrate animal including, but not limited to, a dog, cat, horse, cow, pig, sheep, goat, chicken, primate, e.g., monkey, rat, and mouse with a diabetic condition.
xe2x80x9cSkin disorder,xe2x80x9d as used herein, means a disturbance of function, structure, or both, resulting from exogenous factors such as poison, trauma or disease.
xe2x80x9cDiabetic skin disorder,xe2x80x9d as used herein, means a skin disorders that may occur in any population, but occurs more frequently in subjects having circulatory insufficiencies and/or diabetes.
xe2x80x9cWound,xe2x80x9d as used herein, means a trauma to any of the tissues of the body, especially that caused by physical means and with interruption of continuity.
xe2x80x9cPeroxidized lipid,xe2x80x9d as used herein, means any peroxidized lipid compound useful in the present invention including all natural and/or synthetic analogues of peroxidized lipids or lipid-like compounds which possess the biological activity of peroxidized lipids in the skin, such as the promotion of collagen synthesis in the dermis, and increased blood flow, among other effects. Also encompassed within the term xe2x80x9cperoxidized lipidxe2x80x9d are geometric and stereoisomers of the peroxidized lipids. Biologically active xe2x80x9cperoxidized lipidsxe2x80x9d useful in the methods of the invention include at least one peroxide obtained by the peroxidation of lipids of vegetable origin.
xe2x80x9cComposition including peroxidized lipids,xe2x80x9d as used herein, means a composition including substantial amounts of the previously defined peroxidized lipids. Other materials, or other lipids that do not have the biological activity of the previously described peroxidized lipids may be included in the composition.
xe2x80x9cSubstantial amount,xe2x80x9d as used herein, means at least about 2%.
xe2x80x9cEmollient,xe2x80x9d as used herein, refers to the non-irritating character of the composition as a whole. That is, the nature of the vehicle and amount of peroxidized lipid therein should be selected so as to provide a sub-irritating dose for topical application.
An xe2x80x9ceffective amountxe2x80x9d as used herein, is a dosage of the peroxidized lipid sufficient to provide a medically desirable result.
xe2x80x9cCarrier,xe2x80x9d as used herein, denotes an organic or inorganic ingredient, natural or synthetic, with which the active ingredient is combined to facilitate the application.
xe2x80x9cPharmaceutically-acceptable carrier,xe2x80x9d as used herein, means one or more compatible solid or liquid filler, diluents or encapsulating substances which are suitable for administration onto a human or other animal.
xe2x80x9cLong-term sustained release,xe2x80x9d as used herein, means an implant constructed and arranged to deliver therapeutic levels of an active ingredient for at least 30 days, and preferably 60 days.
The present invention is directed to methods of applying a peroxidized lipid or a composition that includes peroxidized lipids. The method involves the therapeutic application of peroxidized lipids, or compositions containing peroxidized lipids, to treat skin disorders, circulatory insufficiencies, wounds to the dermis, and wounds to the epidermis, by applying the peroxidized lipid or a composition containing the peroxidized lipid, to an area of skin on a subject that includes such a condition. The present invention is based on the surprising discovery that certain peroxidized lipids may modify the wound healing process, and contribute to, inter alia, therapeutically treating subjects having various conditions or disorders including, but not limited to, circulatory insufficiencies, skin disorders, wounds to the skin dermis or epidermis. Although not wishing to be bound by any theory, it is thought that the methods described herein are effective due to the release of free oxygen and/or the promotion of collagen production.
Advantages of treatment with the peroxidized lipids according to the methods of the invention may include, inter alia, increased collagen production, faster wound healing, particularly in diabetics, increased blood flow, and normalizing of the epidermis resulting in smoother, less dry, and less rough skin. Because of this activity, they may promote and accelerate the healing of wounds in compromised tissue. Further, the production of new collagen may repair damaged skin. Still further, treatment with peroxidized lipids according to the present invention may raise the surface temperature of the skin due to greater flow of blood, increasing acuity to pain and irritation, and allowing the skin to become more reactive to chemical insults. Such increased sensitivity of the skin treated with peroxidized lipids may provide an early warning system to older people and diabetics to minimize damage before pain or irritation is felt.
In one aspect, the methods of the invention are useful for treating a wound to the dermis or epidermis. The present method is particularly useful in treating subjects with circulatory insufficiencies or diabetes. Injury to the skin may lead to a number of undesirable health conditions, including, for example, problems with the wound healing process. When problems with the wound healing process become very severe, then management of the wound typically becomes invasive. In some instances of severe circulatory insufficiencies or complications related to diabetes, amputation may be required. Many treatments have been proposed for overcoming such insufficiencies, as well as for alleviating other disorders associated with chronic circulatory insufficiency. One attempt to modify the wound healing process involved the topical application of B-Glucans, a macrophage stimulator, resulting in more rapid epithelization, earlier angiogenesis, increased collagen formation, and increased breaking strength of wounds. Various vitamins and minerals are known to modulate the connective tissue formation phase of wound healing. Others have attempted to modify the wound healing process by stimulating the production or biosynthesis of collagen. One attempt at collagen stimulation includes using vasodilator prostaglandins PGE1 and PGI2, which have shown clinical promise in patients with impaired blood supply from vascular diseases. Stimulation of collagen and glycosaminoglycan deposition, accelerated epidermal regeneration, and stimulation of angiogenesis has been shown in a number of animal wound models by the topical application of epidermal growth factor (EGF). Other agents under study include platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), and transforming growth factors-alpha and beta (TGF%,B).
The conditions and/or disorders described above are not associated with male sexual asthenia, which is a particular category of circulatory insufficiency. Diabetes, in particular, is unrelated to male sexual asthenia. Thus, the preferred group of patients treatable by the methods of the present invention are subjects free of symptoms of circulatory insufficiencies, as well as subjects that are free of male sexual asthenia. The preferred subjects are also otherwise free of any other condition calling for peroxidized lipid treatment, such as being free of symptoms calling for vasodilative or vasoprotective products.
The method according to any of the embodiments of the invention described above involves the application of a composition containing substantial amounts of peroxidized lipids. Preferably, the peroxidized lipids used in the methods of the invention include at least one peroxide obtained by the peroxidation of lipids of vegetable origin, for example, in the form of at least one natural vegetable oil. Such oils are preferably selected from sweet-almond oil, hazelnut oil, peanut oil, maize oil, grapeseed oil, sesame oil and safflower oil. The peroxidized lipids described above may be derived from commercially available compounds using routine chemical procedures known to those of ordinary skill in the art. The peroxidized lipids useful in the methods of the invention are known products prepared from lipids, for example, by saturation with oxygen and intense and controlled exposure to ultraviolet rays, as described in documents: BSM No. 2330 M; EP-A-293 535; FR-A-C-2591 112; EP-A-225 832; EP-A-225 833; EP-A-226 506; FR-A-1 461 744; FR-A-2 539 142; and EP-A-117 961.
The peroxidized lipids used in the methods of the invention may vary in chemical nature, but must necessarily have a degree of peroxidization of between 50 and 200 milliequivalents per kilogram, and more preferably of between 50 and 150 milliequivalents per kilogram measured by the AFNOR method. In one particular embodiment, such peroxidized lipids have a content of oxidized glycerides of between 5 and 40%. A preferred method involves the topical application of a pharmaceutical composition including from about 2 to about 99% peroxidized lipids. Although not required, it is preferred that the pharmaceutical composition includes about 1% of fragrance, as well as pharmaceutically acceptable excipients and demineralized water.
One preferred peroxidized lipid has the general formula: 
where R is an octadecenoic or peroxidized octadecenoic acid, as disclosed in the above-referenced U.S. Pat. No. 5,254,585, which is incorporated herein by reference in its entirety. The composition may also include, for example, lipids with different functional groups, including, but not limited to, septadecenoic or peroxidized septadecenoic acid, or nonadecenoic or peroxidized nonadecenoic acid functional groups.
The peroxidized lipids described above are administered in effective amounts. The effective amount will vary with the particular condition being treated, the age and physical condition of the subject being treated, the severity of the condition, the duration of the treatment, the nature of the concurrent therapy (if any), the specific route of administration, and like factors within the knowledge and expertise of the health practitioner. For example, an effective amount for treating circulatory insufficiency would be an amount sufficient to promote increased blood flow (see examples). Also as an example, an effective amount for treating wounds would be an amount sufficient to halt the development or further progression of necrosis. Thus, it will be understood by those skilled in the art that the peroxidized lipids of the invention may be used to treat circulatory insufficiencies in subjects at risk of developing complications from circulatory insufficiency. It is preferred generally that a maximum dose be used, that is, the highest safe dose according to sound medical judgement.
Generally, doses of the active compound will include between 50 and 200 milliequivalents per kilogram, and preferably of between 50 to 150 milliequivalents per kilogram. It is expected that doses ranging from 50 to 150 milliequivalents per kilogram will be suitable, preferably topically, and one or several administrations per day. In the event that a response on the subject is insufficient at the initial dose is supplied, higher doses (or effectively higher doses by a different, more localized delivery route) may be employed to the extent that patients tolerance permits. Multiple doses per day are contemplated to achieve and maintain a medically desirable result.
When administered, the pharmaceutical preparations of the invention are applied in pharmaceutically-acceptable amounts and in pharmaceutically-acceptable compositions. Such preparations may routinely contain salt, buffering agents, preservatives, compatible carriers, and optionally other therapeutic agents. When used in medicine, the salts should be pharmaceutically acceptable, but non-pharmaceutically acceptable salts may be conveniently used to prepare pharmaceutically-acceptable salts thereof and are not excluded from the scope of the invention. Such pharmacologically and pharmaceutically-acceptable salts include, but are not limited to, those prepared from the following acids: hydrochloric, hydrobromic, sulfuric, nitric, phosphoric, maleic, acetic, salicylic, citric, formic, malonic, succinic, and the like. Also, pharmaceutically-acceptable salts may be prepared as alkaline metal or alkaline earth salts, such as sodium, potassium or calcium salts.
The peroxidized lipids may be combined, optionally, with a pharmaceutically-acceptable carrier. The components of the pharmaceutical compositions also are capable of being co-mingled with the molecules of the present invention, and with each other, in a manner such that there is no interaction which would substantially impair the desired pharmaceutical efficacy.
The pharmaceutical compositions may contain suitable buffering agents, including, for example, acetic acid in a salt; citric acid in a salt; boric acid in a salt; and phosphoric acid in a salt.
The pharmaceutical compositions also may contain, optionally, suitable preservatives to stabilize the composition, and/or prevent the growth of bacteria and/or molds. A variety of suitable materials known in the art of pharmaceutical and cosmetic formulation may be used in this context, for example, methyl paraben, benzalkonium chloride, benzlylparaben, calcium acetate, captan, chloroacetamide, dichlorobenzyl alcohol, DMDM hydantoin, imidazolidinyl urea, isopropylparaben, quaternium-15, sodium benzoate, and the like.
Other components may also be included in the overall composition to impart other desirable properties to the formulation, for example, vitamins, fatty acid esters, ultraviolet light absorbers, peripheral vasodilators such as methyl salicylate and nicotinic acid and its esters, herbal additives, powdered milk, proteolytic enzymes, vegetable powders, fruit extracts, egg solids or oil, starches, clays, amino acids, proteins, astringents, drugs, and the like.
One preferred composition has the characteristics shown below in Table 1.
A variety of administration routes are available. The particular mode selected will depend of course, upon the severity of the condition being treated and the dosage required for therapeutic efficacy. The methods of the invention, generally speaking, may be practiced using any mode of administration that is medically acceptable, meaning any mode that produces effective levels of the active compounds without causing clinically unacceptable adverse effects. According to one particular characteristic of the invention, these products are used for the preparation of a pharmaceutical composition intended for local topical application, and may be in the form of a cream, liquid, solution, gel, soft capsules, or transdermal patches containing the peroxidized lipids.
The pharmaceutical compositions may conveniently be presented in unit dosage form and may be prepared by any of the methods well-known in the art of pharmacy. All methods include the step of bringing the peroxidized lipids into association with a carrier which includes one or more accessory ingredients. In general, the compositions are prepared by uniformly and intimately bringing the peroxidized lipids into association with a liquid carrier, a finely divided solid carrier, or both, and then, if necessary, shaping the product. Other delivery systems may include time-release, delayed release or sustained release delivery systems. Such systems may avoid repeated administrations of the peroxidized lipids described above, increasing convenience to the subject and the physician. Use of a long-term sustained release systems may be particularly suitable for treatment of chronic conditions. Long-term sustained release implants are well-known to those of ordinary skill in the art and include some of the release systems described above.
Thus, one aspect of the invention provides the following benefits: faster wound healing; normalization of the epidermis; and promotion of collagen production. Accordingly, peroxidized lipids promote the formation of a more normal dermis. Because of this activity, they may promote and accelerate the healing of wounds in compromised tissue.
Still further, treatment with peroxidized lipids according to the present invention may raise the surface temperature of the skin due to greater flow of blood, increasing acuity to pain and irritation, and allowing the skin to become more reactive to chemical insults. Such increased sensitivity of the skin treated with peroxidized lipids may provide an early warning system to older people and diabetics so that too much damage is not done before the pain or irritation is felt.
The present invention will be further illustrated by the following examples, which are intended to be illustrative in nature and are not to be considered as limiting the scope of the invention.